docs: def LHCb_label(side="L", status="final", text="", pad=None):
      """Add an 'LHCb (Preliminary|Unofficial)' label to the current pad."""
  
      if pad is None:
          pad = ROOT.gPad
  
      with preserve_current_canvas():
          pad.cd()
          if side == "L":
              l = ROOT.TPaveText(pad.GetLeftMargin() + 0.05,
                                 0.87 - pad.GetTopMargin(),
                                 pad.GetLeftMargin() + 0.30,
                                 0.95 - pad.GetTopMargin(),
                                 "BRNDC")
          elif side == "R":
              l = ROOT.TPaveText(0.70 - pad.GetRightMargin(),
                                 0.75 - pad.GetTopMargin(),
                                 0.95 - pad.GetRightMargin(),
                                 0.85 - pad.GetTopMargin(),
                                 "BRNDC")
          else:
              raise TypeError("Unknown side '{0}'".format(side))
  
          if status == "final":
              l.AddText("LHCb")
          elif status == "preliminary":
              l.AddText("#splitline{LHCb}{#scale[1.0]{Preliminary}}")
          elif status == "unofficial":
              l.AddText("#splitline{LHCb}{#scale[1.0]{Unofficial}}")
          elif status == "custom":
              l.AddText(text)
          else:
              raise TypeError("Unknown status '{0}'".format(status))
  
          l.SetFillColor(0)
          l.SetTextAlign(12)
          l.SetBorderSize(0)
          l.Draw()
  
          keepalive(pad, l)
  
          pad.Modified()
          pad.Update()
  
      return l, None